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CS110/CS119Introduction to Computing (Java)

Dan Pletea

dpletea@cs.umb.edu

S-3-090

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CS110 vs CSIT114/CSIT115

• Two tracks for starting CS curriculum at UMB– CS110 is a traditional one semester introduction

to computer science and Java programming– CSIT114 and CSIT115 are a new two semester

sequence covering the same material (similar to the first two CS courses at a community college)

• Decide which track is correct for you– Some experience with programming CS110– Otherwise, consider CSIT114 and CSIT115

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Welcome to CS110• Textbook is Lewis and Loftus, Java Software

Solutions, Foundations of Program Design, 7th Ed. (The 6th Ed. is also acceptable)

• The course syllabus is on my CS110 website:http://www.cs.umb.edu/~dpletea/cs110

• Go to the UNIX/PC lab (Science Bldg 3rd floor)– “Apply” for a UNIX/PC account– You will need that account to upload your project files

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Welcome to CS110

• I recommend that you print copies of my lecture notes from the web and bring them to each lecture session

• One lab session each week– In one of the Healey Library General Use Labs– Hands-on work associated with the lectures– Lab report must be turned in the following week

• We’ll go through the syllabus now

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Homework Assignments

• We assume that you are computer literate:– Word Processing, Email, Web Browsing,

Downloading Applications, etc.

• Reading for today: L&L, 1.1 – 1.3 & App B– We won’t cover this material in class, but you are

responsible for knowing it in homework or on exams– If you are totally unfamiliar with this material or have a

hard time with it, please see me!

• Reading for next class: L&L, 1.4-1.6, Lab 1: “Using Dr Java and Sun Java SDK”

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Types of Software (Programs)

• Computers are very powerful pieces of hardware that can’t do much useful work until they are properly programmed

• There are three different types of software:– Operating Systems– Application Programs– Software Development Tools (or Kits)

• As a computer programmer, you may need to use and/or write any or all three types of programs

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Operating System Programs

• “O/S” programs control the hardware and allow application programs to be executed

• An O/S is usually built to run on a specific underlying hardware platform, e.g. PC, MAC, or server

• Generally these are the most complex types of programs to write and test

• Examples:– M/S DOS, Windows, UNIX, Linux, Solaris, etc.

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Application Programs

• “Apps” perform useful work for their users • Apps are usually built to run on a specific

operating system (and maybe a specific underlying hardware platform)

• Users typically need to provide a lot of information about their job tasks for a programmer to write a good application program for that purpose

• Examples:– Word, Excel, PowerPoint, Chrome, etc.

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Software Development Tools

• Software Development Tools or Kits (SDK’s) are specialized application programs that allow programmers to write and test programs

• Experienced programmers generally prefer an “Integrated Development Environment” (IDE)

• Examples (that we’ll be using in this course):– Sun’s Java SDK (sometimes called JDK)– Dr Java IDE

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Styles of User Interface

• There are two predominant styles of User Interface for any type of program:– Command Line Interface (CLI)– Graphical User Interface (GUI)

• As a computer programmer, you must be able to use and/or write programs for both styles of user interface

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Styles of User Interface

• Command Line Interface (CLI)– Computer types a “Prompt” requesting input– User types a “Command” with “Parameters”– Predominantly an old style of interaction that

does not require a lot of computer power, but still in use today in some O/S and applications

– Considered to be NOT “user friendly”, but is very efficient when combined with “scripting”

– Example: DOS prompt, command & parameter

C:\ >type file.txt (display the contents of the file)

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Styles of User Interface

• Graphical User Interface (GUI)– Computer displays a combination of text and

graphical symbols offering options to the user– User manipulates mouse and uses keyboard to

select from the offered options (“hot keys”) or to enter text

– More common now (computer power is cheap)– Considered by most to be “user friendly”– Examples: M/S Windows/Office or MAC O/S

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Software Development Tools• Using Sun Java SDK alone

SourceFile(s)(.java)

Programmer

Compiler(javac)

ClassFile(s)(.class)

VirtualMachine

(java)

Editor

Programexecutes

Parts of Sun Java SDK

Command Line Interface

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Using Sun Java SDK Alone

• Example DOS Commands and ParametersC:\ > edit HelloWorld.java

(Create/edit “source file” in an external window)

C:\ > javac HelloWorld.java (creates .class file)

C:\ > java -classpath … HelloWorld

Hello World

C:\ > exit

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Software Development Tools• We will use a combination of the Dr Java IDE

and the Sun Java SDK

SourceFile(s)(.java)

Programmer

Dr Java IDE

Compiler(javac)

ClassFile(s)(.class)

VirtualMachine

(java)

Edit Build Run

Programexecutes

Parts of Sun Java SDK

Graphical User Interface

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On-line Demonstration: Dr Java

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Program Development Steps

Edit and save source code

Build source codeto create program

Run program andevaluate results

Errors

Errors

• Classical “Waterfall” Development Steps

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Errors

• A program can have three types of errors:

• The IDE editor and/or compiler will find syntax errors and other basic problems (compile-time errors)

– If compile-time errors exist, an executable version of the program is not created

• A problem can occur during program execution, such as trying to divide by zero, which causes a program to terminate abnormally (run-time errors)

• A program may run, but produce incorrect results, perhaps using an incorrect formula (logical errors)